1. Field of the Invention
This invention relates to a squeegee head for the printing of bodies by the screen printing method, and is directed more particularly to a squeegee head having a squeegee rubber member, and a holder for gripping the squeegee rubber member.
2. Description of the Prior Art
In known screen printing methods for effecting printing upon the surfaces of bodies, so-called body printing, or package printing, squeegee (or wiper) heads are used, the heads including a rubber member and a holder therefor. The holder typically consists of two adjacently arranged strips extending over the entire length of the squeegee rubber, clamping the squeegee rubber therebetween.
In order to achieve pressure of the working edges of the squeegee rubber on a screen stencil, which is as flat as possible, the elasticity of the rubber material in such known squeegee heads is utilized. This takes place in such manner that the clamping location of the squeegee rubber between the strips is provided at a certain spacing from the working edge of the squeegee rubber. The rubber material present between the working edge and the clamping location then develops, as a result of its elasticity, an even pressure over the entire length of the working edge during application of the working edge to the screen stencil.
It is disadvantageous in such known squeegee heads, that the elasticity of the squeegee rubber declines after only a relatively short period of use, so that the squeegee rubber deflects and is no longer in the position to produce the contact pressure necessary for a satisfactory printing result. This effect, generally known as "wrap-around", makes frequent replacement of the squeegee rubber necessary so that the period of useful life of such constructions is relatively short.
A further disadvantage of such known squeegee heads consists in that they produce an error-free printing result only upon completely flat printing surfaces. On the other hand, if the bodies to be printed have irregularities in the printing surface, for example caused by constructional necessities, or if certain regions of the surface give way during the printing process to varying extents as a result of differing wall thicknesses, errors result in the printed image which lead to a relatively high rejection rate.